Toxicity of 5-fluorouracil for aerobic and hypoxic cells in two murine tumours

Abstract

Chronically hypoxic cells in solid tumours are reported to be more slowly proliferating than aerobic cells situated closer to blood vessels. Cycle-active drugs such as 5-fluorouracil (5-FU) might be expected to have greater activity against rapidly proliferating aerobic cells. The effect of 5-FU was therefore assessed against aerobic and hypoxic cells in murine tumours; this was done by giving the drug alone or 1 h before irradiation of the tumour under aerobic or hypoxic conditions. Aerobic and hypoxic cells appeared to have equal sensitivity to 5-FU in the KHT and 16/C tumours, and the effect of a single dose of 5-FU was additive to that of radiation.